Supporters from the end allocated to Widnes invaded the pitch after the final hooter was sounded on the Vikings' 28-6 defeat and approached rival fans in a provocative manner.

A banner was unfurled and while Castleford fans appeared not to respond to any goading, violence did break out on the field as police and stewards attempted to quell the disturbance.

At least one female spectator suffered a sprained ankle after being caught up in the trouble, the RFL confirmed.

Pictures also emerged via social media of the head being removed one of the Castleford club's tiger mascots and kicked away.

Wood said: "The sport has every right to be disappointed with the behaviour of a minority of Widnes fans. We will work with the clubs to identify any supporters who encroached onto the pitch. There is no place for such behaviour in rugby league.

"True rugby league supporters are renowned for their good nature at all occasions such as this and we will not hesitate to use whatever measures are available to us to protect these precious values."

The RFL will now await reports from relevant parties before deciding on whether to launch an investigation.

A statement read: "Following the incident involving some spectators at the end of the Tetley's Challenge Cup semi-final at Leigh Sports Village between Castleford Tigers and Widnes Vikings, the RFL will await reports from the stadium, the police and the two clubs before deciding what action to take.

"The behaviour of the vast majority of fans was exemplary and the incident was not what is expected from rugby league supporters. This should not detract from two very successful semi-finals."

A number of Castleford players were still on the field when the invasion occurred and were seen attempting to usher supporters back in the direction of the stands.

Tigers coach Daryl Powell said: "We were just trying to get them off the field. It was ridiculous, to be honest. I don't know what they were trying to prove.

"But the boys are all right. There were no real incidents."

Greater Manchester Police were contacted on Sunday evening but unable to confirm whether any arrests had been made.